Chitosan is a β-1,4-linked polymer of glucosamine (2-amino-2-deoxy-β-D-glucose) and lesser amounts of N-acetylglucosamine. It is formed by the deacetylation of chitin (poly-N-acetylglucosamine), an abundant byproduct of the crab and shrimp processing industries.
The water solubility and antimicrobial property of native chitosan can be achieved or enhanced via the quaternization of chitosan. Quaternized chitosan, as a consequence of the quaternization of the amino group in the C-2 position, gained a permanent positive charge on the polysaccharide backbone. Quaternized chitosans find utility in cosmetic preparations, food preservation and packaging, coating materials, disinfectants and biomedical applications (JP-A-2005-290297, JP-A-8-144121, JP-A-2004-515813).
Hence, quaternized chitosan can be utilized for hydrogel formation and formulated as antimicrobial contact lens coating. In order to achieve hydrogel formation, quaternized chitosan can be grafted with photocrosslinkable groups, such as (meth)acrylates, and be converted into hydrogels through a UV polymerization process. Hydrogels are hydrated cross-linked polymeric systems that contain water in an equilibrium state and have been widely used in many biomedical applications including contact lenses, bio-implants such as urinary catheters, pacemaker, heart valves, artificial heart, mammary prosthesis, intraocular lenses, wound dressings, artificial organs and delivery carriers for the bioactive reagents due to their high degree of biocompatibility. However, there have been no studies on the use of quaternized chitosan hydrogels as antimicrobial medical device coating. The present invention describes the formation of novel hydrogels based on quaternized chitosan which has been grafted with polymerizable group, especially photocrosslinkable group, and relates to medical device having resultant antimicrobial activities.